Transmission of Non-B HIV Subtypes in the United Kingdom Is Increasingly Driven by Large Non-Heterosexual Transmission Clusters

Abstract

Background. The United Kingdom human immunodeficiency virus (HIV) epidemic was historically dominated by HIV subtype B transmission among men who have sex with men (MSM). Now 50% of diagnoses and prevalent infections are among heterosexual individuals and mainly involve non-B subtypes. Between 2002 and 2010, the prevalence of non-B diagnoses among MSM increased from 5.4% to 17%, and this study focused on the drivers of this change.Methods. Growth between 2007 and 2009 in transmission clusters among 14 000 subtype A1, C, D, and G sequences from the United Kingdom HIV Drug Resistance Database was analysed by risk group.Results. Of 1148 clusters containing at least 2 sequences in 2007, >75% were pairs and >90% were heterosexual. Most clusters (71.4%) did not grow during the study period. Growth was significantly lower for small clusters and higher for clusters of ≥7 sequences, with the highest growth observed for clusters comprising sequences from MSM and people who inject drugs (PWID). Risk group (P < .0001), cluster size (P < .0001), and subtype (P < .01) were predictive of growth in a generalized linear model.Discussion. Despite the increase in non-B subtypes associated with heterosexual transmission, MSM and PWID are at risk for non-B infections. Crossover of subtype C from heterosexuals to MSM has led to the expansion of this subtype within the United Kingdom.

Phylogenetic evidence for underreporting of male‐to‐male sex among human immunodeficiency virus–infected donors in the Netherlands and Flanders

“…In most western countries the HIV epidemic is still dominated by HIV Subtype B, but many countries have observed a gradual increase in the proportion of HIV non‐B subtypes . Although non‐B epidemics in Western countries remain largely associated with immigrants from countries where non‐B subtypes predominate (e.g., sub‐Saharan Africa), the prevalence of non‐B subtypes further increases as a result of their introduction and dispersal in European MSM, SBMW, or IDU transmission networks . As in the United States and the United Kingdom, HIV Subtype B predominates among HIV‐infected Dutch and Flemish donors .…”

Identifying Transmission Clusters with Cluster Picker and HIV-TRACE

“…[28][29][30][31] Transmission clusters can provide insight into shifts in social and structural dynamics influencing transmission over time and the role of social distance and other structural influences on transmission, independent of participant-reported history. 32 There is great potential for using these data to help identify segments of the population at highest risk for incident HIV infection, which can inform the mechanisms, upper limits of reach, and targeting for network-based HIV testing and care interventions, PrEP, and other social and behavioral intervention.…”

Molecular epidemiology of HIV-1 infection in Europe: An overview

“…Molecular epidemiological analyses revealed that non-B sequences among heterosexuals in the UK were initially strictly linked with strains from sub-Saharan Africa (Hughes et al, 2009), while the C clade viruses have been associated with South America (de Oliveira et al, 2010; United Kingdom Collaborative Group on HIV Drug Resistance, 2014). Nevertheless, a recently published study reported that the prevalence of non-B clades among MSM increased by N 3 times between 2002 and 2010, and, despite the increase in non-B in heterosexual transmission networks, MSM and PWID are still at high risk for non-B infections (Ragonnet-Cronin et al, 2016). In Ireland a similar pattern of increasing prevalence of non-B subtypes acquired through heterosexual exposure has been observed (De Gascun et al, 2012) and the only subtype identified in Iceland was B up until 1993 when the introduction of non-B subtypes was linked to immigration (Del Amo et al, 2011;Löve et al, 2000).…”